【摘要】 对经典的单轴Bouc-Wen模型进行改进,研究建立了可以综合考虑P-效应、捏拢效应、强度退化、刚度退化、应变硬化等典型滞回特性的新型单轴Bouc-Wen模型。根据非弹性单自由度体系在69条强震记录作用下的动力响应,定量地分析了P-效应对地震延性需求的均值和变异系数的影响,进而建立了地震延性需求的经验概率分布模型和预测方程。计算结果显示:由重力引起的P-效应对地震延性需求的影响较大,而由竖向地震激励引起的P-效应的影响很小;地震延性需求与震级、震中矩、剪切波速等参数之间的线性相关性较小;对于短周期体系,可以采用Lognormal或Frechet分布来描述地震延性需求的概率分布,而对于长周期体系,采用Frechet分布则更为合理。更多还原

【Abstract】 An improved uniaxial Bouc-Wen model was developed by taking the P-? and pinching effects,strength and stiffness degradations,as well as strain hardening into account.According to the nonlinear seismic dynamic responses of an inelastic single-degree-of-freedom(SDOF) system under 69 selected earthquake records,the influence of P-? effect on both the mean and coefficient of variation(COV) of seismic ductility demands were quantitatively investigated.The probability distribution type and prediction equation of seismic ductility demand for an inelastic SDOF system with P-? effect were also developed.The analysis results show that the P-? effect induced by the gravity affects significantly the seismic ductility demand,while the effect induced by the vertical seismic excitation is negligible.Linear correlation coefficients between seismic ductility demand and seismic parameters,such as the moment magnitude,epicentral distance and shear wave velocity,are usually unobvious.It also implies that for a short-period system the seismic ductility demand can be modeled as either a Lognormal or Frechet distribution variable,while for a long-period system,the Frechet distribution variable is preferred.更多还原